Well i would have thought you'd get 2-3 stops max out of a monopod, but just remeber that the Sigma is under half the price of the Canon 70-200 f/2.8 IS. I think i can live with no IS and a monopod if it means a lens for half the price. Anyway if you want to discuss this further, you should start a new thread in the tripods section.

As a student, it's hard to get money to buy Lenses. However, I was lucky enough to be in a school which uses canon stuff. Thus, I managed to get loans on my school's 70-200 f2.8. Although it had a fantastic bokeh, I would not buy the 2.8 version, due to its weight. I was at the recent National Day Parade rehearsal, with the borrowed 70-200 f2.8. My hands were aching after 20minutes of free hand shooting! Which made me decide on the f4 version due to its lighter weight. I haven't thought about IS yet.. Also, should i need the f-stops of 2.8, I have my 100mm Macro to cover the low aperture.

I have bought the 2.8 non-IS, because it was just that much cheaper than the IS version. The choice was always between the 2.8 and the 2.8 IS because i loooove bokeh. Ideally of course I'd want the IS, you can always turn it off if you want. If I was loaded I'd swap the lens, but this one produces very nice images too. Te weight is not really an issue for my in terms of muscle-ache, but it does make you want IS just that little more. A heavy lens is more difficult to keep still after all. It's not a matter of big concern, there are a lot of other things I could spend my money on before switching the lens for its IS brother.

Got to this thread a bit late but I own the 70-200L F4 IS and it is awesome!

I opted for the F4 IS version because the 2.8 weighs the proverbial ton and my primary use is out and about in the countryside. I do not want to lug a great weight around for many hours – photography is meant to be pleasurable after all.

Another point to bear in mind is would you actually use F2.8? Most of my shots require depth of field so I generally start at F8 so I would be buying a lot of class for nothing.

One final point. I have the Canon 1.4 teleconverter which turns the lens into a great semi macro. OK your not getting super close with this combo but if you want to capture a butterfly or dragonfly the 100mm is just no good because you have to get to close to the subject – the shot below was taken just over a metre away so the wildlife do not get to worried.

I just thought i'd point out here, that i have a 70-200 f/2.8 (Sigma One, cause i'm a student ) and it's not that heavy at all, i have never once thought about the weight, so if your wondering which lens to go for between the 2.8 and the 4, don't let the weight be a deciding factor, unless your very weak!

I just thought i'd point out here, that i have a 70-200 f/2.8 (Sigma One, cause i'm a student ) and it's not that heavy at all, i have never once thought about the weight, so if your wondering which lens to go for between the 2.8 and the 4, don't let the weight be a deciding factor, unless your very weak!

Machismo aside at 1570g the F2.8 IS weighs considerably more than the F4's weight of 760g.

As I said in my comments, if you intend to use it for extended periods such as all day in the forests/hills I think most people would notice the difference but then again I may just be a very weak tree surgeon!

I bought mine mainly for Sharper Photograph's when I go our Photographing Trains. (Nothing less) I bought my Lens for $600 Dollars at B&H Photo. And I love this L Lens. It hardly ever comes off my Camera. This Lens means more to me than anything that I have ever owned. The good thing is. If the Camera where to ever stop working. I can always buy another Camera and still use this Lens.

First thing I personally feel IS Technology is slightly overrated. It will not function as you may thing, a few stops is not as much as you may hope for. It is a lot less compensating but works very, very well.

I shoot in studio, along with portraits out doors with strobes, so I do not need the IS or the extra stops. I like the F/4 version because the contrast is so so good.

The price is unbeatable for the F/4 version, You can get this version if you like and you can always upgrade to the next if you feel it is inadequate; the resale value is great on this lenses. The focal length is tight on this lens so you will need some room to work it, but it works superb as a portrait lens.

Lastly these are all tools and they all work flawlessly. Budget and functionality will decide. I will say be true to yourself, and try to focus on what you need and not what you can get.

I would have thought flying birds is one situation where IS doesn't matter so much. You'll need a fast shutter to freeze the motion. IS really comes in when you want to use longer shutter times risking camera shake.